2. Light

4. Atomic Structure and Periodicity You should be able to  Identify characteristics of and perform calculations with frequency and wavelength.  Know the relationship between types of electromagnetic radiation and Energy; for example, gamma rays are the most damaging.  Know what exhibits continuous and line spectra.  Know what each of the four quantum numbers n, l, m, and m s represents.  Identify the four quantum numbers for an electron in an atom.  Write complete and shorthand electron configurations as well as orbital diagrams for an atom or ion of an element.  Identify the number and location of the valence electrons in an atom.  Apply the trends in atomic properties such as atomic radii, ionization energy, electronegativity, electron affinity, and ionic size.

5. Copyright © 2007 Pearson Benjamin Cummings. All rights reserved. MOST of the ENERGY is being released as HEAT

6. Light Bulbs Tungsten –F–Filament glows red-hot –M–Moving electrons = friction The flow of electrons is called electricity! Fluorescent –C–Cool-light –E–Electrons become excited and release energy (light) as they fall back to ground state. e e e e e e e e e e e e e e electrons 12 Gauge Wire 8 Gauge Wire

7. Light Bulbs Tungsten –F–Filament glows red-hot –M–Moving electrons = friction The flow of electrons is called electricity! Fluorescent –C–Cool-light –E–Electrons become excited and release energy (light) as they fall back to ground state. e e e e e e e e e e e e e e electrons 12 Gauge Wire 8 Gauge Wire

8. Formation of Light Nucleus e e Lithium Atom + Ground State e e Excited State e Electron Returns to Ground State Light is given off e Ion is formed Li  e + Li 1+ hv n = 1 n = 2 n = 3 n = 4 n = 5 n = 6 n = 7 Nucleus

9. Humor Question: Why does hamburger have lower energy than steak? Answer: Because it’s in the ground state.

10. Light Particles –photons (discrete bundles of energy) Light is emitted when electrons return to ground state from an excited state Waves –Frequency, wavelength Wave-Particle duality

11. Wave-Particle Duality JJ Thomson won the Nobel prize for describing the electron as a particle. His son, George Thomson won the Nobel prize for describing the wave-like nature of the electron. The electron is a particle ! The electron is an energy wave!

12. The Wave-like Electron Louis deBroglie The electron propagates through space as an energy wave. To understand the atom, one must understand the behavior of electromagnetic waves.